1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Extensible Firmware Interface
  4 *
  5 * Based on Extensible Firmware Interface Specification version 2.4
  6 *
  7 * Copyright (C) 2013 - 2015 Linaro Ltd.
  8 */
  9
 10#define pr_fmt(fmt)	"efi: " fmt
 11
 12#include <linux/efi.h>
 13#include <linux/fwnode.h>
 14#include <linux/init.h>
 15#include <linux/memblock.h>
 16#include <linux/mm_types.h>
 17#include <linux/of.h>
 18#include <linux/of_address.h>
 19#include <linux/of_fdt.h>
 20#include <linux/platform_device.h>
 21#include <linux/screen_info.h>
 22
 23#include <asm/efi.h>
 24
 25unsigned long __initdata screen_info_table = EFI_INVALID_TABLE_ADDR;
 26
 27static int __init is_memory(efi_memory_desc_t *md)
 28{
 29	if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
 30		return 1;
 31	return 0;
 32}
 33
 34/*
 35 * Translate a EFI virtual address into a physical address: this is necessary,
 36 * as some data members of the EFI system table are virtually remapped after
 37 * SetVirtualAddressMap() has been called.
 38 */
 39static phys_addr_t __init efi_to_phys(unsigned long addr)
 40{
 41	efi_memory_desc_t *md;
 42
 43	for_each_efi_memory_desc(md) {
 44		if (!(md->attribute & EFI_MEMORY_RUNTIME))
 45			continue;
 46		if (md->virt_addr == 0)
 47			/* no virtual mapping has been installed by the stub */
 48			break;
 49		if (md->virt_addr <= addr &&
 50		    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
 51			return md->phys_addr + addr - md->virt_addr;
 52	}
 53	return addr;
 54}
 55
 56extern __weak const efi_config_table_type_t efi_arch_tables[];
 57
 58/*
 59 * x86 defines its own screen_info and uses it even without EFI,
 60 * everything else can get it from here.
 61 */
 62#if !defined(CONFIG_X86) && (defined(CONFIG_SYSFB) || defined(CONFIG_EFI_EARLYCON))
 63struct screen_info screen_info __section(".data");
 64EXPORT_SYMBOL_GPL(screen_info);
 65#endif
 66
 67static void __init init_screen_info(void)
 68{
 69	struct screen_info *si;
 70
 71	if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
 72		si = early_memremap(screen_info_table, sizeof(*si));
 73		if (!si) {
 74			pr_err("Could not map screen_info config table\n");
 75			return;
 76		}
 77		screen_info = *si;
 78		memset(si, 0, sizeof(*si));
 79		early_memunmap(si, sizeof(*si));
 80
 81		if (memblock_is_map_memory(screen_info.lfb_base))
 82			memblock_mark_nomap(screen_info.lfb_base,
 83					    screen_info.lfb_size);
 84
 85		if (IS_ENABLED(CONFIG_EFI_EARLYCON))
 86			efi_earlycon_reprobe();
 87	}
 88}
 89
 90static int __init uefi_init(u64 efi_system_table)
 91{
 92	efi_config_table_t *config_tables;
 93	efi_system_table_t *systab;
 94	size_t table_size;
 95	int retval;
 96
 97	systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
 98	if (systab == NULL) {
 99		pr_warn("Unable to map EFI system table.\n");
100		return -ENOMEM;
101	}
102
103	set_bit(EFI_BOOT, &efi.flags);
104	if (IS_ENABLED(CONFIG_64BIT))
105		set_bit(EFI_64BIT, &efi.flags);
106
107	retval = efi_systab_check_header(&systab->hdr);
108	if (retval)
109		goto out;
110
111	efi.runtime = systab->runtime;
112	efi.runtime_version = systab->hdr.revision;
113
114	efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));
115
116	table_size = sizeof(efi_config_table_t) * systab->nr_tables;
117	config_tables = early_memremap_ro(efi_to_phys(systab->tables),
118					  table_size);
119	if (config_tables == NULL) {
120		pr_warn("Unable to map EFI config table array.\n");
121		retval = -ENOMEM;
122		goto out;
123	}
124	retval = efi_config_parse_tables(config_tables, systab->nr_tables,
125					 efi_arch_tables);
126
127	early_memunmap(config_tables, table_size);
128out:
129	early_memunmap(systab, sizeof(efi_system_table_t));
130	return retval;
131}
132
133/*
134 * Return true for regions that can be used as System RAM.
135 */
136static __init int is_usable_memory(efi_memory_desc_t *md)
137{
138	switch (md->type) {
139	case EFI_LOADER_CODE:
140	case EFI_LOADER_DATA:
141	case EFI_ACPI_RECLAIM_MEMORY:
142	case EFI_BOOT_SERVICES_CODE:
143	case EFI_BOOT_SERVICES_DATA:
144	case EFI_CONVENTIONAL_MEMORY:
145	case EFI_PERSISTENT_MEMORY:
146		/*
147		 * According to the spec, these regions are no longer reserved
148		 * after calling ExitBootServices(). However, we can only use
149		 * them as System RAM if they can be mapped writeback cacheable.
150		 */
151		return (md->attribute & EFI_MEMORY_WB);
152	default:
153		break;
154	}
155	return false;
156}
157
158static __init void reserve_regions(void)
159{
160	efi_memory_desc_t *md;
161	u64 paddr, npages, size;
162
163	if (efi_enabled(EFI_DBG))
164		pr_info("Processing EFI memory map:\n");
165
166	/*
167	 * Discard memblocks discovered so far: if there are any at this
168	 * point, they originate from memory nodes in the DT, and UEFI
169	 * uses its own memory map instead.
170	 */
171	memblock_dump_all();
172	memblock_remove(0, PHYS_ADDR_MAX);
173
174	for_each_efi_memory_desc(md) {
175		paddr = md->phys_addr;
176		npages = md->num_pages;
177
178		if (efi_enabled(EFI_DBG)) {
179			char buf[64];
180
181			pr_info("  0x%012llx-0x%012llx %s\n",
182				paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
183				efi_md_typeattr_format(buf, sizeof(buf), md));
184		}
185
186		memrange_efi_to_native(&paddr, &npages);
187		size = npages << PAGE_SHIFT;
188
189		if (is_memory(md)) {
190			/*
191			 * Special purpose memory is 'soft reserved', which
192			 * means it is set aside initially. Don't add a memblock
193			 * for it now so that it can be hotplugged back in or
194			 * be assigned to the dax driver after boot.
195			 */
196			if (efi_soft_reserve_enabled() &&
197			    (md->attribute & EFI_MEMORY_SP))
198				continue;
199
200			early_init_dt_add_memory_arch(paddr, size);
201
202			if (!is_usable_memory(md))
203				memblock_mark_nomap(paddr, size);
204
205			/* keep ACPI reclaim memory intact for kexec etc. */
206			if (md->type == EFI_ACPI_RECLAIM_MEMORY)
207				memblock_reserve(paddr, size);
208		}
209	}
210}
211
212void __init efi_init(void)
213{
214	struct efi_memory_map_data data;
215	u64 efi_system_table;
216
217	/* Grab UEFI information placed in FDT by stub */
218	efi_system_table = efi_get_fdt_params(&data);
219	if (!efi_system_table)
220		return;
221
222	if (efi_memmap_init_early(&data) < 0) {
223		/*
224		* If we are booting via UEFI, the UEFI memory map is the only
225		* description of memory we have, so there is little point in
226		* proceeding if we cannot access it.
227		*/
228		panic("Unable to map EFI memory map.\n");
229	}
230
231	WARN(efi.memmap.desc_version != 1,
232	     "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
233	      efi.memmap.desc_version);
234
235	if (uefi_init(efi_system_table) < 0) {
236		efi_memmap_unmap();
237		return;
238	}
239
240	reserve_regions();
241	/*
242	 * For memblock manipulation, the cap should come after the memblock_add().
243	 * And now, memblock is fully populated, it is time to do capping.
244	 */
245	early_init_dt_check_for_usable_mem_range();
246	efi_find_mirror();
247	efi_esrt_init();
248	efi_mokvar_table_init();
249
250	memblock_reserve(data.phys_map & PAGE_MASK,
251			 PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));
252
253	if (IS_ENABLED(CONFIG_X86) ||
254	    IS_ENABLED(CONFIG_SYSFB) ||
255	    IS_ENABLED(CONFIG_EFI_EARLYCON))
256		init_screen_info();
257}